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UNITED STATES PATENT EEicE.

GEORGE H. ENNIS, OF TROY, NEIV YORK, ASSIGNOR TO JESSIE D. ENNIS AND IVILLIAM W. ROUSSEAU, OF SAME PLACE.

PROCESS OF REFINING IRON.

SPECIFICATION forming part of Letters Patent No. 552,056, dated December 24;, 1895.

Application filed March 16, 1883. Serial No, 88,478. (No specimens.)

To all whom it may concern.-

Be it known that I, GEORGE H. ENNIS, acitizen of the United States, residing at Troy, in the county of Rensselaer and State of New York, have invented certain new and useful Improvements in Processes of Refining Iron and Steel; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to practice and use the same.

Continued experiments and experience have shown that both in the puddling-furnace and in the converter of the Bessemer pro; cess the phosphorus and sulphur of the metal under treatment are the latest in the order of oxidation of the injurious foreign substances of the iron, and that in the puddling-furnace the larger the percentages of sulphur and phosphorus the longer must the oxidizing efiect of the blast of air be continued. The continued inj ection of the oxidizing blast of air after the elimination of the carbon and silicon from the crude iron occasions a deleterious effect upon the finished product except in\ those instances where the metal is treated in the presence of abasic bath, and even in those instances is accompanied with a destructive loss of metal owing to the greater affinity of the oxygen of the introduced blast for the iron than for the sulphur and phosphorus.

The object of my invention is to obviate these disadvantages, so as to produce a purified product of the desired physical qualities, and one which has not suffered material loss of metal in passing through the process to which it has been subjected in accordance withmy invention and to the accomplishment of these ends I substitute for the oxidizing blast heretofore employed, in whole or in part, a blast of ammonia-gas, (NH preferably preheated, and prepared from sal-ammoniac and quick lime heated together in any convenient vessel or prepared in any other suitable way.

The ammonia-gas may be forced through the molten metal under treatment by the pressure caused by its retention in the vessel where it is generated, or by any suitable form of blast apparatus. It may be heated as required in any suitable vessel, and it may be used either alone or in connection with an airblast, as hereinafter explained.

The ammonia-gas (NH will be decomposed by passing through the mass of molten metal into its 'constitutent elements, hydrogen and nitrogen. The hydrogen thus set free and in the nascent state will combine with energy with the carbon, silicon, sulphur, and phosphorus of the molten metal under the forms of carbureted hydrogen, sulphureted hydrogen, silicureted hydrogen, and phosphoreted hydrogen, all compounds capable of burning in the air with the evolution of heat, while the nitrogen, having little or no affinity for the iron, will pass through the molten metal and escape with the waste products of combustion.

As ammonia-gas contains no oxygen or other substance capable of injuriously affecting the iron, its use can be continued as long as required to effect the complete elimination of the foreign substances contained in the metal, as already explained.

My process can be used in the puddlingfurnace by first melting the pig-iron by means of the usual blast of air and gas, and oxidizing out the carbon of the molten metal, in whole or in part, after which a blast of ammonia-gas, preferably heated, may be introduced by suitable openings or tuyeres at the bottom of the hearth, Where, by its decomposition into its constituents, hydrogen and nitrogen, the refining of the iron will be completed, as above explained.

In the Bessemer apparatus my process may be carried out as follows The converter having received its usual charge of molten metal ammonia-gas, highly heated and under sufficient pressure, may then be introduced through the usual tuyeres of the converter. In its passage through the molten mass of metal the gas will be decomposed into its constituent elements, hydrogen and nitrogen, the free hydrogen in its nascent state effecting the elimination of the foreign substances, as above more particularly explained.

In lieu of the last-mentioned mode of operation atmospheric air may be forced into the molten mass of metal through the usual tuyeres until the Whole or part of the carbon is eliminated, whereupon the air-blast may be, in whole or in part, shut off and the removal of the remaining foreign substances effected by a blast of ammonia-gas admitted through the tuyeres, preferably in a heated condition. A convenient way of subjecting the metal to the successive action of the air blast and ammonia-blast would be after the air-blast has done its'allotted Work to reduce the air-blast pressure to such a degree as to balance the head of metal in the converter and prevent the metal running back into the tuyeres, after which the blast of highly-heated ammonia-gas can be introduced through the airtuyeres and the refining of the iron completed, as explained.

With either of the above methods the usual method of carburizing the purified product ;then passing through the partially purified product ammonia gas; substantially as described.

3. The process of refining iron which consists in passing through it whi-lein a molten condition, an air blast thereby eliminating in part or wholly the carbon and silicon, and then. passing through the partially purified product, ammonia gas in a pre-heated condition; substantially as described.

GEORGE H. ENNIS.

Witnesses R. N. PU'RDY, G. F. PEoK. 

